1. Field of the Invention
The present invention relates to an object recognition system attached to an autonomous mobile body.
2. Description of the Related Art
Japanese Patent Application Publication No. 53-16230 describes a vehicle collision avoidance system which evaluates danger by detecting distance and relative velocity to an obstacle using a radar, in which when a signal reflected from the obstacle becomes weak making it no longer possible to detect the obstacle, the vehicle collision avoidance system evaluates danger by estimating the distance and relative velocity to the obstacle based on information obtained so far.
Japanese Patent No. 3866328 describes an object recognition system which identifies a three-dimensional object based on a distribution of distance to an obstacle around a vehicle, determines relative position between the vehicle and obstacle, erases the obstacle when the relative position goes out of a predetermined area around the vehicle, memorizes any newly detected obstacle, and determines the likelihood of contact with the vehicle. Since position of the detected obstacle is updated when the vehicle travels, if the same obstacle is detected multiple times, the obstacle is mistaken as multiple obstacles, limiting the movement of the vehicle.
Japanese Patent Application Publication No. 2006-92253 describes an autonomous mobile system which, even when there are multiple obstacles, makes avoidance decision by determining a travel direction and other conditions of the obstacle nearest to the autonomous mobile system without associating the obstacles with each other. The autonomous mobile system determines the travel direction of the obstacle by discrediting a direction component of velocity along two axis in a travel direction of the autonomous mobile system and a direction orthogonal to the travel direction into three values—positive, zero, and negative values—and adding values of past n frames in forward and backward directions as well as in right and left directions.
A robot which travels autonomously at office or home is required to travel without coming into collision with obstacles such as human beings or other robots which behave in a manner similar to human beings. Human beings travel slowly, at uneven speeds. Also, human beings tend to stop or change direction suddenly. In such an environment, the robot needs to determine a travel path by avoiding collisions with obstacles such as the human beings. The technique disclosed in Japanese Patent Application Publication No. 2006-92253 cannot deal with uneven movement of obstacles such as the human beings.